Kerala Tomato Flu – A Manifestation of Hand Foot and Mouth Disease

To the Editors:

Hand-foot-and-mouth-disease (HFMD) is a frequent febrile rash illness of childhood caused by enteroviruses (EV): Coxsackie A16 (CA16), EV A71, Coxsackie A6, Coxsackie B and Echo viruses.¹ Recent media reports from the Indian state of Kerala have highlighted cases of “tomato flu” in young children, described as a febrile rash illness with round, red skin lesions looking similar to tomatoes.² Here we describe a case of “tomato flu”, referred to us by her family doctor.

A 13-month-old girl and her older 5-year brother developed rashes on their hands and legs, 1 week after returning from a 1-month family holiday to Kerala, during May 2022, where they visited friends and relatives in various cities.

During their visit, the local media in Kerala were reporting on a mysterious illness in children, dubbed “tomato flu”. They denied any contact with sick children though they had played with another child who had just recovered from “tomato flu”, a week before returning to the UK.

A week following their return to the UK, both children developed a vesicular rash, with that of the girl’s being more florid (Fig. 1A,B). Neither child had fever nor any other systemic symptoms. Two days later, the girl developed painful oral lesions (not shown), which led to excessive drooling, though the boy’s lesions had already started to heal.

FIGURE 1.: Fleshy vesicular lesions (3-5mm diameter, scale not shown) on the arms and legs, including the palms and soles, of the 13-month old girl (Day 4 of lesions) (A,B). Healing lesions (Day 16 of rash), with little or no scarring (C,D).

Both children attended the pediatric emergency department where viral swabs of the lesions were taken for PCR testing. They were clinically well enough to self-isolate at home pending these results.

Both children were tested for EV. Due to the fleshy vesicular appearance of the rash, the girl’s samples were also tested for monkeypox at a national reference laboratory (Porton Down, Salisbury, UK). The EV PCR was positive for both children, whereas the monkeypox PCR was negative for the girl. EV typing by sequencing was performed at another national reference laboratory (UKHSA-Colindale, London, UK), which was Coxsackie A16.

The lesions continued to heal in both children and by Day 6 in the boy and Day 16 in the infant, the lesions had virtually disappeared with no scarring (Fig. 1C,D).

Phylogenetic analysis showed that the “Kerala tomato flu” partial CA16 sequences shared a most common recent ancestor with a clade from China (2011-2014) (Figure S1, Supplemental Digital Content 1, https://links.lww.com/INF/E793).

The “Kerala tomato flu” in these children was caused by CA16, one of the commonest EV causes of HFMD in India, along with CA6.^3,4 The unusual presentation of the rash in the infant initially made us consider CA6 as the most likely cause, though monkeypox was also a differential, considering the current global outbreaks. As of June 15, 2022, 2103 laboratory-confirmed cases had been reported to the WHO from 42 member states across 5 WHO regions.⁵ Due to increasing local community transmission, many monkeypox cases in the worst affected countries now report no travel history to endemic areas nor any contact with known monkeypox cases. Frontline pediatricians now need to be aware of these various viral rash differentials during their daily practice.

ACKNOWLEDGEMENTS

We thank the children’s mother for her consent and cooperation in the writing of this case report.